Tests results for former Vice President Dick Cheney showed "evidence of a mild heart attack," an aide said Tuesday.

Doctors at George Washington University Hospital checked out Cheney's heart Tuesday morning, after he was admitted to the hospital Monday experiencing chest pains.

Cheney, 69, has a history of heart problems, including four heart attacks -- starting at the age of 37. Aids say he is resting comfortably and is expected to be released from the hospital before the end of the week.

The 86-year-old senator has recovered from the illness, but is now receiving physical therapy for knee surgery he underwent last year.

"Thanks to the great doctors and nurses at Walter Reed, I am making great strides, working between (therapy) sessions and hope to be fully recovered and back at the office in a few weeks," Dole said in a statement.